Sharing stolen source code with everyone is not such a good idea.
The fact that Valves security was breached and that the code was stolen, means that I now have to wait until late next year for a look at HL2. That doesn't impress me one little bit.
The fact that they are changing the code means that there is a good possibility that your maps created with the unofficial beta, will not actually work with the final release. So it seems that getting a head start, will not actually be getting a head start.
You are welcome to post thoughts and ideas but refrain from posting any maps created with the stolen code, as they will be deleted. ( I deleted your billiards room map because you said it was an HL2 map, and since Valve haven't released HL2, the the only people that can view it are people with the illegal beta, I will not support the use of the stolen source.)
I believe that the best course of action would be to follow Kol's and Seventh's advice.... delete and report.